1. Field of the Invention
The invention concerns an apparatus and process for shaping an exposed end of a cosmetic stick.
2. Related Art
Deodorant, antiperspirant and lipstick products have the common characteristic of being comprised of a solid low-melting waxy stick composition encased in a suitable container provided with a means for urging the stick upwards through the container to expose more surface area as the stick is consumed. These cosmetic products have generally been fabricated by pouring the composition in a molten state into a suitable container equipped with a twist-up device.
Subsequent to stick fabrication, there often is a need to achieve a particular shape for the exposed end portion of the stick. Two techniques to accomplish stick end shaping are mechanical trimming and molding.
Illustrative of a molding technique is U.S. Pat. No. 4,369,158 (Woodruff et al) which describes a process wherein a pouring cup is attached to the top of a product container held in a removable manner. A twist-up device having air vents is then inserted into the still molten composition. Once cooled, the pouring cap, operating as a mold to achieve a domed shape on the exposed stick end, is thereafter removed. Among the problems of this method is the necessity for maintaining a molten state after the dome formation to accommodate insertion of the twist-up device. Additional costs are incurred because of this hot insertion. Production line speeds are also adversely impacted by the need to maintain the molten state for insertion of the twist-up device.
Alternative to molding techniques are those of mechanical trimming. Typical of mechanical trimming is EP 0 335 112 (Karavadra) wherein a solid antiperspirant stick is sculpted with a set of heated cutting edges. A precut cutting edge is oscillated in one direction to partially cut into one side of the exposed end of the stick. Rough cut and finish cut cutting edges are then arcuately passed through the end of the stick in the opposite direction. U.S. Pat. No. 4,841,826 (Smith) trims by notching a deodorant bar on one side and a rough cutter moves inwardly through the other side of the body to enter the closed end of the notch and sever body material without breaking. Thereafter a finish cutter removes relatively little material to produce a finish cut.
EP 0 359 905 (Allison et al) reports a method and apparatus for trimming solid stick deodorants wherein the stick is brought into registration with a means for raising an end thereof to a predetermined height. The stick is then transported into registration with a rotating knife to impart a rounded oval configuration to an end thereof. Thereafter the stick is transported to another conveyor means and then trimmed product is released for further packaging. A plurality of arcuate knives progressively in succession trim respective portions of the solid deodorant stick so as to provide the oval configuration.
There are several problems with the known trimming art. Single edge knives such as in EP 0 359 905 tend to trace a flat area rather than the desired oval shape. This is one reason for requiring a plurality of such blades to compensate for the limitation in providing rounded edges. Reduction in the number of blades can be accomplished by increasing the number of passes per blade over the subject stick end. Speed is, however, compromised thereby. Moreover, it is quite difficult to operate with multiple blades on wider samples because of the radius of the resultant cut; too high an arc in a finished product appears aesthetically unappealing.
The known art also suffers from the significant disadvantage that changing from one product shape to another requires significant time delay in readjusting or changing blade types.
Accordingly, it is an object of the present invention to provide an apparatus and process for shaping an end of a solid cosmetic stick that operates at a greater speed than previously achievable.
Another object of the present invention to provide an apparatus and method for shaping an end of a solid cosmetic stick that can rapidly convert between different trim profiles.
It is still another object of the present invention to provide an apparatus and method for shaping an end of a solid cosmetic stick that achieves sharper and more appealing aesthetic profiles.
These and other objects of the present invention will become more readily apparent through consideration of the embodiments that follow.